In data storage devices, buck-boost regulators are often utilized to generate negative preamp bias voltage. Fixed frequency regulators operating discontinuous conduction mode have historically been the solution of choice, as their design and operating characteristics are well understood within the data storage device industry. However, such implementations suffer from important shortcomings. In these discontinuous conduction mode regulators, stability requires careful control loop design, particularly at the higher loop bandwidths often necessary to achieve acceptable transient performance. Even these high bandwidth solutions provide, at best, modest transient response. Further, operating in discontinuous conduction mode necessitates relatively high peak inductor current to ensure regulator output power requirements are met.
Embodiments of the present invention provide solutions to these and other problems, and offer other advantages over the prior art.